Bomb hunted in London in new IRA drive . . .

Police kept part of London's main shopping street sealed off Tuesday as they searched for a bomb believed planted by Irish guerrillas in a renewed terror campaign on the British mainland.

A civilian explosives expert was killed Monday as he tried to dismantle a bomb in an Oxford Street hamburger shop, while a second bomb was defused in a department store. That was the third such attack in London in 16 days, but the first against a nonmilitary target.

The Irish Republican Army, which admitted responsibility, said in a warning telephoned to the Reuters new agency that three bombs were planted. The third, which the IRA said was placed in a department store, was no found.